Following a visit to Jordan in November, Representative Rob Wittman, R-Virginia, argued the campaign against the Islamic State (ISIS) “needs an Arab face.” Saudi Foreign Minister Saud Al-Faisal agreed, declaring success “requires the presence of combat troops on the ground.”

It is a notion shared by Jordan’s King Abdullah as well. During an interview with PBS’s Charlie Rose, Abdullah said, “We, as Arab and Muslim countries…need to take ownership of this.”

Rhetoric comes easily, but implementation does not. When pressed by Rose about deploying Jordanian troops the king demurred, noting “at the end of the day, whether it’s in Iraq or in Syria, it has to be done by the local populations themselves.”

Here lie the limits of the anti-ISIS coalition: U.S. partners in the region are unable or unwilling to do more.

Key reasons for this reticence include limited capability, Iraq’s uninterest in foreign troops, regional tensions and fear of domestic blowback. U.S. allies in the region invest heavily in air power, but their conventional land forces remain limited (Saudi Arabia, UAE, Qatar and Bahrain), or outdated (Jordan).

The coalition’s contribution to date is limited: of 1,219 airstrikes conducted in Iraq and Syria since August, coalition partners contributed 208.

Second, Iraq’s leaders have dismissed the idea of foreign troops. Saudi Arabia has stationed 30,000 troops along the Saudi-Iraq border since July and reports from September hinted at possible Jordanian deployment, but Iraqi Prime Minister Haider al-Abadi has emphasized, “Not only is it not necessary,” he said, “We don’t want them. We won’t allow them. Full stop.”

Third, existing regional tensions make a cohesive coalition unlikely. While Qatar and the United Arab Emirates (UAE) both joined NATO operations in Libya in 2011, they are now on opposite sides of a regional proxy war, with Qatar backing the parliament in Tripoli, while the UAE, other Gulf states and Egypt back the parliament based in the eastern Libyan city of Tobruk. Qatar supports Egypt’s Muslim Brotherhood, while Saudi Arabia backs Abdel Fattah al-Sisi’s regime.

Amid these competing regional rivalries, even the backdrop of a growing ISIS threat may not be sufficient to create unity among Arab League or Gulf Cooperation Council members.

Finally, the potential for domestic blowback concerns regional leaders. Most ISIS fighters appear to be Iraqi or Syrian, yet the topthree states of origin for foreign fighters joining ISIS are Tunisia and Saudi Arabia, followed closely by Jordan. ISIS’s continued advance threatens neighboring states, and returning fighters could destabilize regional governments, but with many citizens distrustful of U.S. policy in the region further participation in the coalition could spark domestic protest as well.

Could the coalition ever overcome these challenges? It is difficult to imagine how. Short of an about-face by Iraq’s leadership, or a sudden thawing of tension in the Gulf, the dysfunction will likely continue. Overt U.S. pressure on regional partners might backfire, yet in absence of broader participation from the coalition, the United States should plan to assume much of the operational burden going forward.